Improving mechanisms for searching vast numbers of documents, such as those available via the World Wide Web (“web”) or on large enterprise computer networks, has increasingly been an area of focus and research. This is especially due to the continued growth in the number of computer users, services and applications offered for example on the web, and the amount of information being added to the web, enterprise computer networks and other databases.
A search engine or search engine program is a widely used mechanism for allowing users to search vast numbers of documents for information. Conventional search engines index the documents and the terms appearing in the documents. A term can be a string of characters or groups of strings of characters representing a one or more related words. Generally, a search engine provides a user interface that includes a query field. A user can enter one or more search terms describing the desired information in the query field. In response to a query, the search engine attempts to locate relevant documents by matching the search terms to the indexed terms appearing in the documents. Based on these matches, the search engine ranks, sorts and then returns for display the search results, usually as a list of relevant documents.
Typically, the concept or concepts represented by the search terms or the terms in the documents are not taken into account. A concept can be a normalized semantic representation that can be expressed with any number of terms. Methods of complex searching exist, but most of these methods of complex searching are term based. For example, an advanced Boolean search or an advanced text search are both based on terms and not concepts. With a term search, documents are converted into a list of terms with relative rankings and the document's terms are compared with the search terms. Term searches can provide poor results when faced with terms having multiple meanings, the use of synonyms, and important terms that are not used frequently. Further, it is difficult to search for a concept using term-based searching methods. For example, if it is desired to search all documents that mention the concept “California cities”, each city must be enumerated as a search term.
In order to provide a concept-based search, a search engine can utilize a network of concepts. While such networks of concepts exist, these conventional networks generally associate concepts in a hierarchical fashion and provide no weight to the associations. Further, such conventional networks of concepts are not easily editable.